It has been recognized that small concentrations of metal ions play an important role in biological processes. For example, Mn, Fe, Ca, Zn, Cu and Al are essential bio-metals, and are required for most, if not all, living systems. Metal ions play a crucial role in oxygen transport in living systems, and regulate the function of genes and replication in many cellular systems. Calcium is an important structural element in the life of bacteria regulating enzyme activity. Mn, Cu and Fe are involved in metabolism and enzymatic processes. At high concentrations, metals may become toxic to living systems and the organism may experience disease or illness if the level cannot be controlled. As a result, the availability, and concentrations, of metal ions in biological environments is a major factor in determining the abundance, growth-rate and health of plant, animal and micro-organism populations.
It has also been recognized that iron is an essential biological element, and that all living organisms require iron for survival and replication. Although, the occurrence and concentration of iron is relatively high on the earth's surface, the availability of “free” iron is severely limited by the extreme insolubility of iron in aqueous environments. As a result, many organisms have developed complex methods of procuring “free” iron for survival and replication.
Articles, such as food and beverage containers are needed that are able to improve food quality, to increase shelf-life, to protect from microbial contamination, and to do so in a manner that is safe for the user of such items and that is environmentally clean while providing for the general safety and health of the public. Materials and methods are needed to prepare articles having antimicrobial properties that are less, or not, susceptible to microbial resistance. Methods are needed that are able to target and remove specific, biologically important, metal ions while leaving intact the concentrations of beneficial metal ions.
During the process of filling containers with certain beverages and foods, air borne pathogens enter the containers after the flash pasteurization or pasteurization part of the process. These pathogens such as yeast, spores, bacteria, etc. will grow in the nutrient rich beverage or food, ruining the taste or even causing hazardous microbiological contamination. While some beverages are packaged by aseptic means or by utilizing preservatives, many other beverages, for example fruit juices, teas and isotonic drinks are “hot-filled”. “Hot-filling” involves the filling of a container with a liquid beverage having some elevated temperature (typically, at about 180-200° F.). The container is capped and allowed to cool, producing a partial vacuum therein. The process of hot filling of beverages and foods is used to kill the pathogens, which enter the container during the filling of the beverage or food containers. Hot filling requires containers be made of certain materials or constructed in a certain fashion such as thicker walls to withstand the hot filling process. The energy required for hot filling adds to the cost of the filling process. Temperatures required for hot filling have a detrimental effect on the flavor of the beverage. Other methods of filling such as aseptic filling require large capital expenditures and maintaining class 5 clean room conditions.
U.S. Pat. No. 5,854,303 discloses a polymeric material incorporating a polyvalent cation chelating agent in an amount effective to inhibit the growth of a protozoan on the surface of contact lenses and in other eye care products.